//构造函数
function Student (name ,age, sex){
    // var this = {
               //name:''
               //age:''
    // }
    this.name = name
    this.age = age
    this.sex = sex
    this.grade = 2019
    //return this
   // return [] function(){}  {}会改变return返回值
}
//console.log(Student()) //undefined
var student =new  Student('帅帅',20,'boy')
console.log(student)

//构造函数的内部原理:(当被new的时候)
//1. 在构造函数体内最前面隐式加上 this={}
//2. 执行 this.xxx = xxx
//3. 隐式的返回this

function myPerson(name,age){
    var that = {}
        that.name = name
        that.age = age
        return that
}

var per1 = myPerson('帅',20)
var per2 = myPerson('家君',20)
//console.log(per1,per2)